Rosa canina is a member of the genus Rosa that has long been used for medical objectives. Several studies have reported cytotoxic effects of different Rosa species, but there has been only limited investigation of the cytotoxic effect of R. canina. The purpose of the current study was to examine the potential effect of R. canina extract on cell viability, the cell cycle, apoptosis, and the expression of telomerase in human colon cancer (WiDr) cells. The cytotoxic effect of the extract was determined using MIT assay. The mechanism involved in the cytotoxic effect of the extract was then evaluated in terms of apoptosis and the cell cycle using flow cytometry. Mitochondrial membrane potential (MMP) was investigated using the fluorometric method, and expression levels of telomerase were studied using RT-PCR. R. canina extract exhibited a selective cytotoxic effect on WiDr cells compared with normal colon cells. The extract induced cell cycle arrest at the S phase and apoptosis via reduced MMP in WiDr cells. R. canina extract significantly repressed telomerase expressions at treatment times of 48 and 72 h in WiDr cells. Our results suggest that R. canina may have considerable potential for development as a novel natural product-based anticancer agent. (C) 2018 Xi'an Jiaotong University. Production and hosting by Elsevier B.V.